Answer:
D. Anaerobic
Step-by-step explanation:
The human body gets energy by breaking a terminal phosphate from adenosine triphosphate (ATP), a high energy molecule. In the cells, ATP is produced during cellular respiration.
Cellular respiration may be aerobic or anaerobic. Aerobic respiration occurs in presence of oxygen and yields 38 ATP from the oxidation of one glucose molecule whereas, anaerobic respiration occurs in absence of oxygen and yields only 2 ATP from the oxidation of one glucose molecule.
Normally human body fulfils its energy requirement by aerobic respiration. But when energy is a requirement is more during running a race, doing heavy exercises, aerobic respiration alone does not fulfil energy requirement, in such condition the body fulfil its required energy through anaerobic respiration in an oxygen-deficient environment.